Update top level architecture description.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@2687 57a11ea4-9604-0410-9ed3-97b8803252fd

src/doc/design/top-level.texinfo

@@ -5,8 +5,8 @@ GnuCash currently consists of the following modules.
 
 @section The Engine
 
-The @dfn{Engine} (located under the src/engine directory in the GnuCash
-codebase) provides an interface for creating, manipulating, and
+The @dfn{Engine} (located under the @file{src/engine} directory in the
+GnuCash codebase) provides an interface for creating, manipulating, and
 destroying three basic financial entities: Accounts, Transactions (known
 as Journal Entries in accounting practice), and Splits (known as Ledger
 Entries). These three entities are the central data structures of the
@@ -15,10 +15,25 @@ GnuCash financial data model.
 The Engine code contains no GUI code whatsoever, and is essentially
 OS-neutral.
 
+@subsection Query
+
+The @dfn{Query} module (@file{src/engine/Query.*}) provides an interface
+into the engine for finding transactions based on a set of criteria,
+such as description, date posted, account membership, etc. Simple
+queries can be combined using standard boolean operators.
+
+@subsection File I/O
+
+The @dfn{File I/O} module (@file{src/engine/FileIO.*}) provides an
+interface for reading and writing a set of Accounts, Transactions, and
+Splits to a binary file. This module is being deprecated. A text-based
+format using scheme forms is being developed as a replacement. This new
+module will be separate from the Engine.
+
 
 @section The Register
 
-The @dfn{Register} (located under src/register) implements a ledger-like
+The @dfn{Register} (@file{src/register}) implements a ledger-like
 GUI that allows the user to dynamically enter dates, prices, memos
 descriptions, etc. in an intuitive fashion that should be obvious to
 anyone who's used a checkbook register. The code is highly configurable,
@@ -28,9 +43,9 @@ example, one can define a ledger with three date fields, one price
 field, and four memo fields in a straightforward fashion. Cell handling
 objects support and automatically validate date entry, memo entry
 (w/auto-completion), prices, combo-boxes (pull-down menus), and
-multi-state check-boxes. Cells can be marked read-write, or output-only.
-Cells can be assigned unique colors. The currently active ledger
-row-block can be highlighted with a unique color.
+multi-state check-boxes. Cells can be marked read-write, or
+output-only. Cells can be assigned unique colors. The currently
+active ledger row-block can be highlighted with a unique color.
 
 The register code is completely independent of the engine code, knows
 nothing about accounting or any of the other GnuCash subsystems. It
@@ -40,38 +55,80 @@ accounting.
 
 @section Reports
 
-The @dfn{Reports} module (src/reports) is a scheme (guile) based system
-to create balance sheets, profit & loss statements, etc. by using the
-engine API's to fetch and display data.
+The @dfn{Reports} module (@file{src/scm/report.scm},
+@file{src/scm/reports}) is a scheme (guile) based system to create
+balance sheets, profit & loss statements, etc. by using the engine
+API to fetch and display data formatted in HTML.
+
+This module is being redesigned to use the Query API to fetch the engine
+information instead of using the raw engine interface. The new reporting
+design will use Queries to extract the data and assemble it into a
+view-independent format. This data will then be converted to HTML
+reports and/or graphs such as bar and pie charts.
+
+
+@section Graphs
+
+The @dfn{Graphs} module will be a future module implementing GUI graphs
+such as bar and pie charts. These graphs will be interactive in that the
+user can, for example, move pie wedges, and 'live' in that the user will
+be able to click on graph subsections to see a detail graph or report of
+that particular subsection.
+
+This module will be implemented using the GUPPI library being developed
+by Jon Trowbridge (@url{http://www.gnome.org/guppi}).
+
+
+@section Price Quotes
+
+The @dfn{Price Quotes} module (@file{src/quotes}) is a Perl system to
+fetch stock price data off the Internet and insert it into the GnuCash
+Engine. This module requires the functionality of the Finance::Quote
+module available at SourceForge. The Finance::Quote module can fetch
+price quotes from many different sources including Yahoo, Yahoo Europe,
+and some international exchanges.
+
+The Finance::Quote module also supports fetching currency exchange
+rates. GnuCash will be extended to allow the fetching and use of
+currency exchange rates.
+
+
+@section User Preferences
 
+The @dfn{User Preferences} module (@file{src/scm/options.scm},
+@file{src/scm/prefs.scm}) provides an infrastructure for defining both
+user-configurable and internal preferences. Preferences are defined in
+scheme using several predefined preference types such as boolean,
+string, date, etc. Preferences are 'implemented' by providing a GUI
+which allows the user to see and change preference values. An API
+is provided to query preference values and to register callbacks
+which will be invoked when preferences change.
 
-@section Quotes
+Preference values which are different from the default values
+are stored as scheme forms in a user-specific preferences file
+(@file{~/.gnucash/config.auto}). This file is automatically
+loaded upon startup.
 
-The @dfn{Quotes} module (src/quotes) is a perl system to fetch stock
-price data off the Internet and insert it into the GnuCash Engine. This
-is now a separate project called Finance::Quote available at
-SourceForge.
 
+@section QIF Import
 
-@section Options
+The @dfn{QIF Import} module (@file{src/scm/qif-import}) provides
+functionality for importing QIF (Quicken Interchange Format) data
+into GnuCash.
 
-The @dfn{Options} module (src/scm/options.scm) provides an
-infrastructure for defining both user-configurable and internal options
-or 'preferences'. User-configurable options are 'implemented' by
-providing a GUI which allows the user to see and change option values.
 
 @section GnuCash
 
-The GnuCash module (src/gnome, src/register/gnome and src/*.[ch]) is the
-main GUI application. It consists of a collection of miscellaneous GUI
-code to glue together all of the pieces above into a coherent,
-point-and-click whole. It is meant to be easy to use and intuitive to
-the novice user without sacrificing the power and flexibility that a
-professional might expect. When people say that GnuCash is trying to be
-a "Quicken or MSMoney look/work/act-alike", this is the piece that they
-are referring to. It really is meant to be a personal-finance manager
-with enough power for the power user and the ease of use for the
-beginner.
+The GnuCash module (@file{src/gnome}, @file{src/register/gnome} and
+@file{src/*.[ch]}) is the main GUI application. It consists of a
+collection of miscellaneous GUI code to glue together all of the pieces
+above into a coherent, point-and-click whole. It is meant to be easy to
+use and intuitive to the novice user without sacrificing the power and
+flexibility that a professional might expect. When people say that
+GnuCash is trying to be a "Quicken or MS Money look/work/act-alike",
+this is the piece that they are referring to. It really is meant to
+be a personal-finance manager with enough power for the power user
+and the ease of use for the beginner.
 
 Currently, the Gnome interface is the only operational interface. There
 is an obsolete Motif interface which is not maintained. The Qt code